Has the particle effect "blockcrack" been removed? It's still listed on this page: http://minecraft.gamepedia.com/Particles
I recently upgraded a 1.8 map to 1.9.2, and I had the following particle command working fine:
/particle blockcrack_3 ~ ~2 ~ 1 1 1 0.5 100
For those that don't know, the number used after blockcrack is determined by the formula: blockcrack_(id+(data*4096)), so a value of 3 should generate dirt particles.
I was having trouble with this myself. I also found that iconcrack and blockdust also do not work.
That's done it! Thanks!